Anyone who wishes to run adventures in the campaign may do so if they can follow these simple guidelines.

Power Scale
The #1 thing that will set the tone of a campaign is the average distribution of power within it. A campaign where the most powerful individuals in the world are around 10th level is a very different experience from a campaign where every bar is owned by a 10th level fighter and every city has a 20th level wizard. In the latter, mighty beasts such as hydras, trolls, and wyverns are of no concern at all, while in the former they are frightful creatures that would give pause and nightmares to most who beheld them.

This campaign is squarely set on the former end of the scale. As a rule of thumb, here's a table with a general estimate of how creatures of a particular CR impact the world.

CR

General Considerations

0-2

Relatively normal people and animals. From bakers to soldiers, most of the people of the world fall into this range.

3-5

Heroes and dangerous beasts. A single warrior capable of breaking a squad of enemy soldiers. A healer who can restore sight to the blind.

6-8

Heroes of great renown. Prophets. Magical creatures who may have cults dedicated to them as deities. Creatures and villains that can bring ruin to settlements.

9-11

The most powerful people in the world. Warriors capable of waging war on nations. Magicians able to bind powerful spirits to their will and create false life. Avatars and servants of the gods.

12-14

Minor deities or demigods that pull the strings in the world and count many worshipers among their followers.

15-17

Lesser deities or demigods that can perform great miracles and do things thought impossible.

18-20

Moderate deities or demigods that are immortal and believed capable of anything.

The seven true gods of Alvena. Believed a myth. They watch and wait for those who will find them.

Campaign Resources
Naturally since the campaign is fairly skewed to the lower end of the power scale, it's important to get an idea of what sorts of things are routinely available in the campaign world. If something requires an 11th level character to accomplish, it requires one of the most powerful characters in the world. As a result the following things should be kept in mind.

Large cities are the biggest settlements in the campaign.

As a result, the purchase limit for magic items is 8,000 gp (do not include cost of base item for weapons and armors).

Spellcasting services are up to 6th level spells in such settlements.

Most magic items are crafted by sufficiently high level Adepts rather than heroic characters.

Most magic items that reproduce high level spell effects are created with limited charges.

As a result, if you need to use high level magic for something, such as justifying a 12 HD outsider being present in the world via a planar binding spell or similar, it's more likely that the effect was created through a limited use magic item or some complex ritual requiring expensive material components than it is the spell was simply cast by an 11th level wizard.

Building Adventures

As one might expect from the power scale of the world, it's generally a good idea to stick to lower CR creatures when filling your GM toolbox. Avoid routinely using high or even middling CR enemies as mooks and throw-away NPCs. A creature such as a Rakshasa (CR 10) would be able to secretly control a city or influence a nation, and so such a creature shouldn't just be found wandering the hallways of any old dusty ruin unless there's a pretty good explanation for it.

There are some exceptions to this with creatures that are fairly simple. It's not particularly world shaking if there are trolls and giants wandering the hillsides. Nor would it be particularly strange to find larger fire elementals around an old volcano. It's one of those points that the GM might have to make a judgment call from time to time. The best rule of thumb is to consider how much the creature could influence the world if left to their own devices. A frost giant is big and brutish but can be defeated by a town militia throwing lots of alchemist fires at it easily enough. A succubus however can travel the span of the world in the blink of an eye, lurk about on the ethereal plane, appear to be anyone, telepathically charm and dominate people, and could easily throw an entire city into chaos without ever revealing themselves. As a result, even though the frost giant is a higher CR (11) the succubus (7) should probably be handled with a bit more respect from a narrative standpoint.

More with Less: With this in mind, build adventures with more low CR things than high CR things. With decent numbers of enemies and decent tactics, low level creatures are often more exciting (and harrowing) to fight than individual higher level foes. It generally takes more cooperation with party members to handle mixed groups of enemies supporting each other. It also mitigates "burst tactics" since each individual enemy or challenge represents a smaller % of the overall encounter. A troll with a poor initiative may never take a turn as a party dogpiles them with their most powerful attacks and knocks them down in the first round. However, in an encounter of 19 orcs warriors, 2 orc adepts, and an orc bard, even if each party member downs three enemies a turn, the battle will go for several rounds.

This also makes higher CR enemies stand out more when they show up.

Encounter Scaling: One of the reasons using lots of lower CR enemies is because it makes adjusting encounters up and down a rather painless process. There are many times you may be GMing for groups with a higher or lower average level than expected. Using lower individual CR creatures allows you to rapidly scale an encounter by adding or removing enemies without changing the encounter around so much.

Generally when planning your adventures, it's easier to think of each encounter you want the players to face as CR X+Y, where X is the average level of the party, and Y being a difficulty modifier for the encounter. For example, an "epic" difficulty in Pathfinder is described as APL+3, while an "easy" encounter is APL-1, so for a 2nd level party an epic encounter is CR 5, but for a 6th level party it would be CR 9. Thus when you're planning adventures, rather than planning specific encounters of a certain challenge rating, instead plan based on the difficulty you want the encounters to be.

For example, you might be building an adventure that involves tracking down some goblins but you don't know the levels of the characters that will participate ahead of time (very normal for a persistent world campaign). So you might make notes that look like this:

And so on. This can be a convenient shorthand for building adventures ahead of time when you don't know what PCs are going to be involved. It makes outlining adventures much faster and easier too during the conceptual process. When you go to run the adventure, you can simply choose an encounter of the appropriate CR (so if you're running an adventure for 3rd level PCs, your Hard encounter will be CR 5, but if you're running it for 5th level PCs it will be CR 7).

The 25% Rule: The d20 system (and Pathfinder) are designed on the assumption of a 4-player party. Naturally this number can vary, especially in a persistent world where the number of available players can fluctuate drastically depending on individual schedules and interest. That's what the 25% rule is meant to handle.

The 25% rule is simple. Every player over 4 increases the XP budget of the encounters by +25%. Every player under 4 decreases it by -25%.

Thus, if your adventure calls for a CR 5 encounter (1600 XP), but you only have 2 players, you use 800 XP worth of enemies and treasures (technically a CR 3 encounter). If you have 5 players, you would instead use 2000 XP worth of enemies and treasures. This allows you to very quickly build very elaborate encounters for groups of any size without stress or worrying about the encounters being too hard or too easy.

When adjusting up for number of players, favor adding more low-XP value monsters and obstacles rather than increasing the individual power of monsters. For example, a party of 8 3rd level characters would warrant an encounter with 1600 XP worth of enemies, but a single CR 5 winter wolf worth 1600 XP has a 6d6 breath weapon that can 1-shot most of the characters if not the whole party, whereas adding 800 XP worth of extra goblins and wolves would make for a more interesting encounter.

Encounter Pallet: When building adventures, consider creating a collection of monsters and traps that you can "drag and drop" into the game as needed. An encounter pallet might look something like this.

A list of the types of creatures you could see being in the adventure or could fill certain roles, with varying XP values. You could do something similar if you were running an adventure in a haunted crypt, which might include a list of creatures ranging from humble skeletons with no equipment to wights that drain levels. The same can be done for traps of different XP values as well.

The purpose of this is to quickly help you build encounters for characters of different levels. For example, you might know that your adventure calls for a "hard" encounter that involves goblins riding on dogs shooting bows at people. If you're running it for a 1st level party, you might have a pair of goblin warriors riding on regular dogs in a comical fashion (the dogs are clearly too small to serve as proper mounts but the goblins don't seem to care) whose total XP value is 540 XP. Or you might be running it for a 4th level party and instead have a pair of elite 3rd level goblin warriors riding on worgs whose value is 1600 XP. It could be scaled up for even higher levels by changing those worgs into winter wolves, and so on.

Generally speaking, when scaling encounters up, it's often an opportunity to get creative with circumstances. For example, a fight with an ogre is pretty neat. A fight with an ogre on a hill with wind gusts that threaten to knock down medium and small sized creatures is even more adventurous. You're not even using a different ogre. You just added some sort of location, terrain, or obstacle that makes the situation more dire. Lots of interesting things can be replicated by using the game's trap mechanics. For example, a natural sinkhole in a forest might be represented in game as a pit trap. Plants with poisonous spores might be a poison gas trap. Crumbling architecture could be a deadfall trap, and so forth.

Putting it All Together
Using the guidelines above, let's make a quick adventure. Our idea is simple. We want the party to deal with a bunch of goblins and their canine minions. We want them to have a tough run in with the goblins early in the adventure in a field of tall grass, give them a chance to lick their wounds after the fight, then track down the goblins to their lair, where they face many of the goblins before facing down the goblin's leader in an underground throne room.

We go to run the game and we find that there will be 3 players, who are 1st, 2nd, and 4th level. We add their levels together and divide by the number of players to find their Average Party Level is 2 (rounded down). So suddenly our adventure now consists of a CR 3 (800 XP), CR 1 (400 XP), CR 2 (600 XP), and CR 4 (1,200 XP) encounter. However, since there's only 3 players we reduce the XP budgets for each encounter by 25%, giving us a final total of 600 XP, 300 XP, 450 XP, and 800 XP.

When the players reach the field, they encounter a pair of goblin warriors riding on dogs (540 XP).
When the players reach the hallyway, they find three roaming goblin warriors without their consumable items (300 XP).
When the players reach the armory, they find three goblin warriors that do have their consumables (400 XP).
When the players reach the throne room, they find a 3rd level goblin warrior (400 XP) and his 2nd level sorcerer companion (400 XP).

Awarding Experience and Treasures

Due to the nature of persistent worlds, players are frequently swept up into all sorts of things at the spur of the moment. Keeping track of treasure can be a headache compared to the traditional tabletop experience where characters typically work with the same characters every adventure. As a result, the treasure rewards in the game are simplified as follows.

Encounter Rewards
For every encounter in your adventure (including non-monster encounters such as traps, hazards, or negotiations) players earn experience points and treasure based on the CR of the encounters they participate in. The actual equipment and items found during the adventure are ignored (see Looted items below).

Award each character that participated in the encounter 1/4th the XP and treasure for that CR.

For example, a CR 5 encounter is worth 1600 XP and 1,000 GP. Every player earns 400 XP and 250 gp for that encounter (even if you scaled encounters up and down using the 25% rule for larger or smaller parties).

Looted Items: Often times NPCs carry items that are of some value, ranging from consumables like potions and scrolls to armaments like armor, weapons, or magical items. There's something quite satisfying about finding great and exotic treasures, or wresting a flaming cold iron sword from a hobgoblin chieftain and claiming it as your own. However, managing who looted what from whom, when, and where, or resolving disputes over who wants what item is a nuisance that over complicates things in a persistent world environment.

Because of this, players are allowed to use any equipment that they find during an adventure as they see fit. However, such items are not retained after the adventure or session of the adventure. At the end of a session or adventure, the GM may include any items of note along with the treasure values each player got over the course of the session. Players may then "purchase" items from that list at 1/2 their market value immediately. Each player can purchase said items individually. Those items are then permanently added to their sheets and carried over into other adventures as normal.

For example, Johnny the GM runs an adventure that consists of six CR 5 encounters, and at the end of those encounters each player who participated earned 1500 gp. During the adventure, the party found several items of interest, including a +1 ring of protection (2,000 gp), a potion of fly (750 gp), and a suit of full plate armor (1500 gp), and a +2 belt of giant strength (4,000 gp). The party members could purchase any of those items at 1/2 cost at the end of the adventure. If they didn't earn enough from the adventure to cover the 1/2 cost of the item (such as with the belt of giant strength) they can spend any gold they have have saved to cover the difference (if a player had 500 gold from outside the adventure, they could put that 500 gp towards the belt of giant strength when the adventure ended). Each player that participated in the adventure is allowed to purchase from the list (so even if there was only a single +1 ring of protection, more than two players may still purchase it).

Once the player has been given the option to purchase the item, they must do so immediately, or at least before they participate on any other adventures with the character. Any items they do not purchase from the hoard are assumed to have been sold off for the GP reward they received at the end of their adventure.

Treasures of Opportunity: Players may do with as they please any treasures they find in this fashion, including selling them to other player characters, much as if they had crafted the item themselves. For example, an adventurer who finds a +1 flaming sword worth 8,000 gp might purchase it at the end of the adventure for 4,000 gp, and then sell it to another player who didn't participate in the adventure for a marked up price that's still less than 8,000 gp. Such trades are not only fine but quite encouraged.